I just got my sync meter for webers and I was just curious what I should set each carb to. Last night I set them all at 6 on the meter and seems to run well. The directions said to set at 2 but anything below 4 and the engine stalls. Also I am in the process of uploading a quick video on you tube so I will post a link to how the car sounds as of now. This is my first 914 so I am not sure how it should sound. It is a 72` 1.7l.
Im posted a few weeks about a compression problem.That is now fixed and I have about 110 to 120 on all 4 cylinders. The bigest problem I have now is that cylinder #1 now backfires through the carb when I get on it. The procedure only says to adjust with the air bypass screws completely closed. I am still not sure what the proper adjustment is for the air bypass screws.
Thanks

Hers is a link to you tube.

http://www.youtube.com/watch?v=XnwNAiQ_oSM

I just found my link and see that proper idle will be a reading od 4-6 or so ( sorry for being a dumb a**). I think that part is good but I am still not sure of the following. If the car sounds like it is running correctly and also what adjustments I should make for the air bypass screws. I still get a strong smell out of the exhaust.

There is considerable disagreement on this one. My CB Weber booklet says something like "smoother idle and better mileage sometimes can be achieved with about 1.5 turns out from closed". My 2 liter likes two turns out. You might wanna check the valve adjust on that backfiring intake, or it could be a clogged jet too. Get a spare set of plugs. Monkeying with carb settings will foul plugs pretty fast on my car and it can turn into a real do loop.

your motor is an air pump.
the syncrometer is measuring just air.
Your motor will only pump a certain amount of air and that is based upon the camshaft (you have not said what cam is in there) the valve sizes, and the venturis.

If you disconnect the crossbar linkage, use only the air mixture screw and the syncrometer to find the fastest flowing venturi.
Turn that venturi down till the motor stalls...turn that venturi out 1/4 turn again.
Using the syncrometer, adjust the other three venturis to match the first one.
From there, you can turn down each one 1/8 of a turn, but this is a very very touchy setting, so go slow, let it settle down each time.

After you have matched the carbs at idle, then and only then should you hook up the crossbar linkage. Then you are just adjusting the linkage, the air screws are locked down.

Rich

1 1/2 Turns out. Are you talking about the air bypass screw or the mixture screw.My original problem is that it was smoking (white) at first but I made some adjustments to the air by pass screw and now it does not smoke but it stanks.I will double check the valve adjustment but that was a nightmare in itself.I had a hell of a time getting it where it is now. I am still not sure if it is correct. I had a post earlier and got a lot of help but like I said I have no good procedure to use so I am kind of blind right now. I know that carb adjustment is based off of a good running engine thats why I posted the link to the video of my car at idle.

the air bypass screws are for making up small possible difs measured at each venturi. 2 schools of thought. just close them completely and run as is or as the cb book suggests, 1/2 out from fully seated. the 1/2 out allows for very small, precise tuning of one or more venturis. what ever you do EACH one MUST be set the same at the start of the 'tunning' of the carbs. they allow air to be drawn in prior to the throttle plates. if one(or more) is open too much, you may experience a lean condition on that specific throat/venturi resulting in the snapping back thru one or both of the carbs. go back to the cb book, disconnect the linkage at the throttle plate shaft. reread the pre-install setup instuctions and set the idle speed screws, idle air mixture screws, and the air bypass screws at the suggested points. start your car. measure the flow at the 2 front venturis. adj one or the other idle speed screws to make the flow the same side to side while sustaining a (hopefully) smooth idle. now measure the flow at all 4 venturis. if one is low you will need to turn the air by-pass in. this is usually a VERY small adj. as mentioned, one valve (or more) out of whack can have a profound impact on the carb dial in.

if you can pinpoint which carb is sneezing back thru the venturi that's the one to look at first. dealing with the air by-pass is fairly simple. no luck? i'd try closing all 4, baseline the idle air mixture screws at the 3 turns out the book suggests, set the idle with the linkage off using the idle speed screws, now measure flow at each venturi. they should be the same. in a perfect world. keep us posted.

Dodntcha just love writing a big long post and having the %%#&* connection fail when you try to load it? GGGRRRRR!!
Synopsis:
yes, the bypass screws (slot screw head w/ lock nut)
try 1/2 turn out on those. Black smoke means rich, white smoke means lean.

Has anyone gone to my link above to verify if this how a running 914 should sound? I think I am close so any feed back would be great. It is the second post.

i can't note anything thing other than a stable idle. what is the idle speed? can you make a vid with the engine exibiting the snapping back thru the carbs? what rpm does that happen at?

k

Yes, I just did.
Your valves are way to loose...
Your not firing on all four cylinders the same....

You cannot adjust your carbs correctly if your valves are that far out, or that different...sounds like one valve is out of adjustment.

Rich

Here is what I do and it is very simple.
Make sure the throttle plates open both to wide open at the same time.
Mess with the linkage arms untill you get it.

THEN
tighten the throttle cable till the engine runs at about 1500 rpm. This should have both carbs off the idle stop screws and all the slack out of the linkage. It also represents how you DRIVE the car throttles open.

now get the synch tool and adjust the link reach rod to attain both carbs pulling the same amount of air. both 8 or 18 or anywhere inbetween it don't matter as long as they are the same.

Now loosen the cable till you are resting back on the idle stops. disconnect one side and then fuss around with the idle stop screws till you get them even and idling at about 900 RPM

Then reattach linkage arms and you will be golden.

I like your idea joe R.

I have a small question about the use of the synchronometer...

the rubber plug has two holes that match up to two holes in the base of the snail. do you guys recommend aligning them (thereby letting air in down low) or closing them and all the air goes through the gauge plate?

thanks

Screw each bypass screw all the way in, and find the barrel that's pulling the most air, then balance the other barrels to that. So there's no static setting, as you should have one that's closed all the way.

Use the search feature to find "carb tuning".

turning the rubber base to the 'hole to hole' position lessens the needle jumping around factor due to the pulsing at idle. if the needle is dancing around you're not going to get an acurate reading. when you think you have them perfect, use one idle adj screw to bring the idle up to 1800rpm or so. this should smooth out the pulsing and needle movement, and you can turn the base to the holes closed position just to double check. if they aren't equal side to side you can now adj one drop link to match the carbs up.

I remember that I had a bear of a time getting the valves where they are now. When I got the car the valves never fully seated. I guess thats the right way to describe it. I measured the gaps and they ranged from .010" to about .040" (when I got the car). It was farting like crazy and smoking real bad. Also the pickup sucked. I aligned the gaps to .006" but I at some point I was not sure if I was on the exhaust stroke or the compression stroke. I had no timing marks on my flywheel so I relied on looking at the valve as I rotated the wheel. I guess it is possible that I am still not TDC for each valve so I will need to go back and check. If I am off is there an easy procedure for adjustment. I tried the tech article at pelican parts but it was confusing. I never did this before.
Thanks

doesn't really matter as long as they're all the same. each motor (and carbs) will be different, so any reference numbers are ballpark figures at best.


if it runs and idles fine at 6, than that's your magick number. like i said, just make sure all 4 are the same and you don't have any air leaks ...
Andy

I've always done it it the way Joe describes AND the way 9146986 describes. Use the throttle cable to bring it up off idle and the "snail" to adjust your linkage. Then disconnect the linkage, find the bore that's flowing the MOST and bring the others up to it with the bypass screw.

The actual numbers are arbitrary, but on all my motors a "5" at idle was typical.

-Aaron